Summary: October 10, 2003 22:2 Geophysical Journal International gji2064
Geophys. J. Int. (2003) 155, 609­622
Can the Earth's dynamo run on heat alone?
David Gubbins,1, Dario Alf`e,2,4
Guy Masters,3
G. David Price2
and M. J. Gillan4
1School of Earth Sciences, University of Leeds, Leeds LS2 9JT
2Research School of Earth Sciences, Birkbeck College and University College London, Gower Street, London WC1E 6BT
3IGPP, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0225, USA
4Physics and Astronomy Department, University College London, Gower Street, London WC1E 6BT
Accepted 2003 June 20. Received 2003 May 6; in original form 2001 July 5
SUMMARY
The power required to drive the geodynamo places significant constraints on the heat passing
across the core­mantle boundary and the Earth's thermal history. Calculations to date have
been limited by inaccuracies in the properties of liquid iron mixtures at core pressures and
temperatures. Here we re-examine the problem of core energetics in the light of new first-
principles calculations for the properties of liquid iron.
There is disagreement on the fate of gravitational energy released by contraction on cooling.
We show that only a small fraction of this energy, that associated with heating resulting from